Catalyzed metal foil and uses thereof

ABSTRACT

Systems, methods, and devices related to catalyzed metal foils are disclosed. Contemplated metal foils have a bottom surface, preferably roughened to Ra of at least 0.1 μm, bearing a catalyst material. The metal foils are etchable, typically of aluminum or derivative thereof, and is less than 500 μm thick. Methods and systems for forming circuits from catalyzed metal foils are also disclosed. The catalyst material bearing surface of the metal foil is applied to a substrate and laminated, in some embodiments with a thermoset resin or thermoplastic resin therebetween or an organic material first coating the catalytic material. The metal foil is removed to expose the catalyst material, and a conductor is plated to the catalyst material.

This application claims the benefit of priority to U.S. patentapplication Ser. No. 17/174,759 filed Feb. 12, 2021, which in turnclaims the benefit of priority to U.S. Provisional Patent No. 63/119,950filed Dec. 1, 2020, which in turn claims the benefit of priority to U.S.Provisional Patent No. 63/066,508 filed Aug. 17, 2020, which in turnclaims the benefit of priority to U.S. Provisional Patent No.62/976,110, filed Feb. 13, 2020, each of which is incorporated byreference in its entirety herein.

FIELD OF THE INVENTION

The field of the invention relates to methods and systems formanufacturing conductive patterns.

BACKGROUND

The following description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

As competition in manufacturing electric circuits continues to driveprofit margins down, improvements must be made in the simplicity,efficiency, and cost effectiveness of manufacturing protocols in orderto maintain a competitive edge in the market. For example, U.S. Pat. No.4,006,047 to Brummett et al (“Brummett”) teaches using a mylar filmsoaked in an electroless plating catalyst solution to thermally transferthe catalyst onto a substrate for electroless deposition. However,shipping pre-soaked mylar films creates issues of the mylar materialdecomposing over time and further shelf-stable, shipping, and durabilityissues. Also mylar has low melting and decomposition temperature and itdoes not withstand the original shape under 150° C. or highertemperature. This limits this material and technique usage for thethermoplastic materials which usually have cure temperature of 150° C.or higher. Further, requiring a user to soak the mylar in catalystsolution is unnecessarily complicated, limiting the market user base forthe product.

All publications identified herein are incorporated by reference to thesame extent as if each individual publication or patent application werespecifically and individually indicated to be incorporated by reference.Where a definition or use of a term in an incorporated reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein applies and the definitionof that term in the reference does not apply.

Partially addressing durability, U.S. Pat. No. 7,740,936 to Ogawa et al(“Ogawa”) teaches applying nuclei of electroless plating catalyst to ametal foil, which improves durability of the product. However, Ogawadoes not teach using such foils to transfer catalyst to substrates forplating, for example using the metal foil as a sacrificial transfermedium.

Thus, there is still a need for improved methods and systems and devicesfor simply, efficiently, and cheaply patterning catalyst onto substratesto form electric circuits, and methods of manufacturing such circuitstherefrom.

SUMMARY OF THE INVENTION

The inventive subject matter provides systems, methods, and devicesrelated to catalyzed metal foils, as well as uses thereof and devicestherefrom. A metal foil has a bottom surface with a catalyst materialdisposed on at least part of the bottom surface of the metal foil, withthat part of the bottom surface typically roughened, for example viaetching or dendrite growth, or in some embodiments oxidized, orcombinations thereof. The metal foil is etchable or otherwise removable,and is preferably one of aluminum, anodized aluminum, copper, tin, oralloys thereof. The metal foil is preferably less than 500 μm thick, forexample less than 400 m, 300 m, 200 m, 100 m, 80 μm, 60 μm, 50 μm, orless than 10 μm thick. In some embodiments, a part of the bottom surface(e.g., the roughened by dendrite growth portion, roughened by etchingportion, etc.) has an arithmetic average roughness (Ra) of at least 0.1m, 0.15 m, 0.2 m, 0.25 m, 0.3 m, 0.35 m, 0.4 m, 0.45 m, or at least 0.5μm.

The catalyst material includes a catalyst precursor for at least one ofAg, Au, Pt, Pd, Cu, Ni, Co or Rh in some embodiments. Alternatively, orin combination, the catalyst material includes at least one of catalyticAg, Au, Pt, Pd, Cu, Ni, Co or Rh. The catalytic material is typicallydisposed as an ink utilizing an organometal precursor such asorganometal compound (e.g., as metal ink, reduced metal ink, thermallyreduced metal ink, etc.) as a layer with a thickness of between theatomic radius of a component of the catalytic material (e.g., catalyticmetal, Ag, Au, Pt, Pd, Cu, Ni Co or Rh, etc.) and 500 m. The organometalcompound can be stabilized by chelating or interacting of counteranions. Alternatively, or in combination, the catalytic material isdisposed (e.g., metal ink, reduced metal ink, chemically reduced metalink, etc.) as a plurality of particles with an average radius of betweenthe atomic radius of a component of the catalytic material (e.g.,catalytic metal, Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, etc.) and 100 nm. Insome embodiments, the ink includes some metal particles (of one or moremetals) that provide for relatively thicker applications of ink orcatalyst precursor, for example by avoiding unstable catalyst precursorconditions due to high concentration of precursor in the ink.

The catalyst layer may also be deposited by sputtering, by evaporation,or chemical vapor deposition.

The inventive subject matter further contemplates systems and methods offorming electrical circuits, as well as circuits formed therefrom.Methods of forming an electrical circuit are contemplated using a metalfoil with a surface having a catalyst material. The surface of the metalfoil with the catalyst material is applied to a surface of a substrate,and the metal foil is laminated to the substrate. The metal foil(preferably etchable or removable metal foil) is then removed (e.g.,etched, etc.), exposing the catalyst material on the surface of thesubstrate. A first conductor is then electroless metal plated to theexposed catalyst material. Further conductors can be plated (e.g.,electrolytic plating) and additional metal foils can be laminated to theconductors and etched as required by an electrical circuit pattern.Metal foils including such layers, and as described below, are of theinventive subject matter.

In some embodiments, the surface of the metal foil with the catalystmaterial is coated by a coating layer of either a B-stage (curable)thermoset resin (e.g., epoxy resin, polyimide precursor, urethane resin,acrylic resin) or a thermoplastic material, or a combination thereof,which is referred to herein as Resin Coated Catalyzed Foil (RCCF™). Insome embodiments, the coating layer is a laminate material (e.g.,conventional resins used for laminate such as epoxy resin for FR4,conventional resins used for resin coated foils (RCF) such as R-FR10(Panasonic) and conventional resins used for bonding film such as ABF(Ajinomoto fine techno)) The resin coated metal foil is then laminatedto the substrate, with the coating layer adjacent to the substrate. Themetal foil (preferably etchable or removable metal foil) is then removed(e.g., etched, etc.), exposing the catalyst material on the surface ofthe coating layer (e.g., where coating layer is B-stage resin,lamination cures it to C-stage resin, etc.). A first conductor is thenelectroless metal plated to the exposed catalyst material. Furtherconductors can be plated (e.g., via electrolytic plating) and additionalmetal foils can be laminated to the conductors and etched as required byan electrical circuit pattern.

In some embodiments, the catalyst material is (i) a catalyst precursorfor at least one of Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, or (ii) at leastone of catalytic Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, or combinationsthereof. In some methods using a catalyst precursor, the catalystprecursor is reduced (e.g., thermal reduction, chemical reduction, etc.)to a catalyst before the step of applying the surface of the metal foilto the surface of the substrate, in some embodiments after the metalfoil has been etched. The metal foil is typically made of one ofaluminum, anodized aluminum, copper, tin, and alloys thereof. In someembodiments, an adhesive layer is applied between the surface of themetal foil having the catalyst material to the surface of the substrate.

In some embodiments a pre-ceramic polymer, a ceramic or a composite ofmetal oxides, polymers or oxidized metal particles, nitrides borides,etc., is coated on a surface the metal foil or on a surface of thecatalyst layer, or both. A coating layer can further coat the layerdeposited on the catalyst material, not to exceed 500 μm, 100 μm, 10 μm,or 1 μm thick. The thickness depends on the coating material.

A layer of an organic material can further be disposed on the catalystmaterial layer no more than 10 μm, 5 μm, 1 μm, 0.5 μm, or 0.1 μm thick.The catalyst material layer is preferably no more than 500 nm, 100 nm,50 nm, or 20 nm thick. The organic material is preferably a copolymerwith an alkaline-reactive polymer portion and an alkaline-non-reactivepolymer portion. In preferred embodiments the copolymer further includesa functional group with a lone pair electron, or otherwise includes atleast one of nitrogen or sulfur. Preferred alkaline-reactive polymerportions have at least one polyimide, amide, ester, or thioester.Generally, the copolymer has a composition of alkaline-reactive polymerportion to alkaline-non-reactive polymer portion of between 5%:95% and95%:5% by molecular weight, respectively.

The organic material is preferably selected to protect the catalystmaterial from diffusion of the catalyst material (e.g., during thermalprocess, lamination, etc.), or otherwise displacement or damage to thecatalyst material or its catalytic activity. In some embodiments theorganic material is selected to improve bonding strength of the catalystmaterial to a substrate or absorb mechanical stress between the catalystlayer and a substrate due to temperature change. The organic material isselected to have at least 25%, 50%, 75%, or 100% greater adhesion (e.g.,mechanical, chemical, dispersive, diffusive, electrostatic, etc.) to asubstrate than the catalyst material has to the substrate.

Methods can further include a step of applying a plating resist in anegative circuit pattern onto the exposed catalyst material before thestep of electroless metal plating. The plating resist is then preferablyremoved (e.g., etched, etc.) after the step of electroless metalplating. It is also contemplated that, before the step of electrolessmetal plating, an etching resist is applied in a positive circuitpattern onto the exposed catalyst material. The catalyst material notcovered by the etching resist is then removed (e.g., etched, etc.), withthe etching resist preferably removed thereafter. In some embodiments, aplating resist is further applied over the first conductor in a negativecircuit pattern, and a second conductor is electrolytically deposited toexposed portions of the first conductor. The plating resist ispreferably removed, and portions of the first conductor not covered bythe second conductor are further removed.

In some embodiments, a permanent plating resist is further applied in anegative circuit pattern onto the exposed catalyst material, before thestep of electroless metal plating. After electroless plating, it iscontemplated that a second conductor is electrolytically deposited tothe first conductor, and an etching resist is applied over the secondconductor in a positive circuit pattern. The first and second conductornot covered by the etching resist are preferably removed, as is theetching resist.

In some embodiments, a metal is plated to a surface of the substrate. Anetching resist layer is further applied in a pattern of a circuit, or atleast part of the pattern of a circuit, onto the metal plated surface.The metal not covered by the etching resist layer is etched from thesurface. The etching resist is then removed from the surface, leavingplated metal in the shape of the pattern or part of the pattern.

Systems and methods for producing a metal foil are further contemplated.A portion of a metal foil is coated with a catalyst ink, with thecatalyst ink coating having a precursor dissolved in a solvent. Thecatalyst ink coating is then dried on the metal foil, followed byreducing (e.g., thermal reduction, chemical reduction, etc.) thecatalyst precursor to deposit a catalyst (e.g., active, etc.) on theportion of the metal foil, which is preferably etchable or otherwiseremovable. The metal foil is typically one of aluminum, anodizedaluminum, copper, tin, or alloys thereof, and is preferably less than500 μm thick, for example less than 200 m, 100 m, 80 μm, 50 μm, 30 μm,20 μm, or less than 10 μm thick. In some embodiments, the portion of themetal foil coated by catalyst ink is roughened, for example by etchingor dendrite growth, or oxidized, or combinations thereof. Alternativelyor in combination, that portion of the metal foil has an Ra of at least0.1 m, 0.15 m, 0.2 m, 0.25 m, 0.3 m, 0.35 m, 0.4 m, 0.45 m, or at least0.5 μm. In some embodiments the precursor ink includes metal particles,or one or more metals.

The catalyst is typically at least one of Ag, Au, Pt, Pd, Cu, Ni, Co, orRh, and is optionally disposed as a layer with a thickness of betweenthe atomic radius of a component of the catalyst (e.g., catalytic metal,Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, etc.) and 500 m. Alternatively or incombination, the catalyst is disposed as a plurality of particles withan average radius of between the atomic radius of a component of thecatalyst and 100 nm. The catalyst ink is typically coated to the metalfoil by at least one of dip coating, roller coating, spray coating,spinner coating, bar coating, curtain coating, blade coating, air knifecoating, cast coating, screen printing, gravure printing, offsetprinting, flexography printing, inkjet printing or combinations thereof.In some embodiments, the portion of the metal foil coated by metal inkis one complete surface (e.g., one complete side) of the metal foil.

Methods of forming electrical circuits with a substrate using a metalfoil are contemplated. A film is laminated to a surface of thesubstrate, and a surface of the metal foil is laminated to the film. Themetal foil is removed to expose a portion of the film or substrate, anda conductor is deposited on the portion of the film or substrate.

The film is preferably partially or fully cured, for example partiallyor fully cured before the step of removing the metal foil, after thestep of laminating the film to the substrate, or after the step oflaminating the metal foil to the film. The film is typically a bondingfilm, for example one of a B-stage resin sheet, a reinforced B-stageresin sheet, or a prepreg

In some embodiments the film or substrate (or metal foil) is treatedwith a chemical, either before and separate from the above method or asa step in the method, for example before removing the metal foil, afterlaminating the film to the substrate, before or after laminating themetal foil to the film, or after removing the foil. The chemical usedfor treating the film or the substrate is typically one or more of anoxidizer such as a solution of permanganate salts (potassiumpermanganate, sodium permanganate, etc.) or the like, and alkali metalor alkali earth metal hydroxides (lithium hydroxide, sodium hydroxide,potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontiumhydroxide, barium hydroxide, etc.). It is also contemplated that a drychemical treatment can be used, such as a plasma treatment, a coronadischarge treatment, or an electron beam treatment, applied for exampleas simultaneous treatment, sequential treatment, or combinationsthereof.

Further steps include applying a catalyst precursor to the film orsubstrate and activating the catalyst precursor to a catalyst before thestep of depositing the conductor to the portion of the film orsubstrate. In some embodiments the surface of the metal foil bears acatalyst or a catalyst precursor. Preferably the surface of the metalfoil carries a catalyst or a catalyst precursor (whether activated ornot) before the step of laminating the surface of the metal foil to thefilm. The catalyst or catalyst precursor (whether activated or not)remains on the film or substrate after the step of removing the metalfoil in preferred embodiments. Typically the catalyst precursor isactivated before depositing the conductor, whether before laminating tothe film, after chemical treatment, or after removing the metal foil.

Where a catalyst or activated catalyst precursor is used, the conductoris deposited by electroless deposition to the catalyst (or activatedprecursor). As a further step, another (e.g., different, same, etc.)conductor is electrolytically deposited (e.g., flash deposition) to thefirst conductor.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a flow chart for producing a catalyzed metal foil of theinventive subject matter.

FIG. 2A depicts a catalyzed metal foil of the inventive subject matter.

FIG. 2B depicts another catalyzed metal foil of the inventive subjectmatter.

FIG. 3A depicts steps of a method of the inventive subject matter.

FIGS. 3B to 3D depict further steps in the method of FIG. 3A.

FIG. 4A depicts steps of another method of the inventive subject matter.

FIGS. 4B to 4D depict further steps in the method of FIG. 4A.

FIG. 5 depicts steps of yet another method of the inventive subjectmatter.

FIG. 6 depicts steps of still another method of the inventive subjectmatter.

FIG. 7A depicts steps of another method of the inventive subject matter.

FIGS. 7B to 7D depict further steps in the method of FIG. 7A.

FIG. 8 depicts steps of still another method of the inventive subjectmatter.

FIG. 9A depicts steps of another method of the inventive subject matter.

FIGS. 9B to 9D depict further steps in the method of FIG. 9A.

FIG. 10 depicts a flow chart of a process of the inventive subjectmatter.

FIG. 11 depicts a flow chart of another process of the inventive subjectmatter.

FIG. 12 depicts a flow chart of yet another process of the inventivesubject matter.

FIG. 13 depicts a flow chart of still another process of the inventivesubject matter.

FIG. 14 depicts starting and end product of a process of the inventivesubject matter.

DETAILED DESCRIPTION

The inventive subject matter provides systems, methods, and devicesrelated to catalyzed metal foils, as well as using such foils to formelectrical circuits and the circuits formed therefrom.

FIG. 1 depicts a flow chart for producing a catalyzed metal foil of theinventive subject matter.

FIG. 2A depicts catalyzed metal foil 200A of the inventive subjectmatter. Catalyzed metal foil 200 includes metal foil 210, which isetchable or removable and typically one of aluminum, anodized aluminum,copper, tin, or alloys thereof, has surface 212. Catalyst 220 isdeposited onto surface 212, typically by coating surface 212 with acatalyst ink having a precursor for catalyst 220 and reducing thecatalyst ink to deposit catalyst 220 onto surface 212. Surface 212 ispreferably roughened, for example having an Ra of at least 0.1 m, 0.15m, 0.2 m, 0.25 m, 0.3 m, 0.35 m, 0.4 m, 0.45 m, or at least 0.5 μm. Insome embodiments, optional layer 230A can be further coated overcatalyst 220 (or, before reduction, over the catalyst ink, etc.).Optional layer can be one or more polymers as described herein, or canbe a pre-ceramic polymer, a ceramic or a composite of metal oxides,polymers, oxidized metal particles, nitrides or borides (e.g., titaniumdioxide, zirconium dioxide, cerium dioxide, Yttrium oxide, or compositesof these with per-ceramic polymers, epoxies that may be A staged, Bstaged or C staged). In some embodiments that include optional layer230A, for example where optional layer 230A includes one or morepre-ceramic polymer, a ceramic or a composite of metal oxides, a furtheroptional layer 240 can be further coated over optional layer 230A. Insuch embodiments, further optional layer 240 typically includes one ormore polymers.

FIG. 2B depicts an embodiment of catalyzed metal foil 200A, labeled200B, where the optional layer is organic material layer 230B. Organicmaterial 230B is a copolymer including an alkaline-reactive polymer andan alkaline-non-reactive polymer, and is typically no more than 1 μm to0.1 μm thick. In some embodiments the copolymer further includes afunctional group with a lone pair electron, for example nitrogen orsulfur. Preferred alkaline-reactive polymers have at least onepolyimide, amide, ester, or thioester. Generally, the copolymer has acomposition of alkaline-reactive polymer to alkaline-non-reactivepolymer of between 5%:95% and 95%:5% by molecular weight, respectively.

FIG. 3A depicts method 300 for manufacturing catalyzed substrate 360Ausing catalyzed metal foil 310. In step 330, surface 314 (havingcatalyst 316) of catalyzed metal foil 310 is laminated to surface 322 ofsubstrate 320 (e.g., prepreg, curable film, thermoplastic substrate),producing interim material 340. In step 350, removable metal foil 312 isremoved (e.g., etched, etc.) from interim material 340, formingcatalyzed substrate 360A having catalyst 316 deposited onto substrate320. In some embodiments, catalyzed metal foil 200A can be used in placeof catalyzed metal foil 310, for example including optional layer 230Aor further optional layer 240 as described. In such embodiments,catalyzed metal foil 360A will appear as catalyzed metal foil 360Bincluding optional layer 230A as depicted in FIG. 3B, or catalyzed metalfoil 360C including optional layer 230A and further optional layer 240as depicted in FIG. 3C. In the embodiment of FIG. 3D, catalyzed metalfoil 200B is used in place of catalyzed metal foil 310, includingcatalyzed metal foil 360D with organic material layer 230B as previouslydescribed.

FIG. 4A depicts method 400 for manufacturing partial circuit 460A usingcatalyzed substrate 310 of FIG. 3A. In step 410, temporary resist layer430 is formed across catalyst 422, deposited on substrate 420 (e.g.,dielectric substrate). Temporary resist layer 430 is formed leavingnegative pattern 432 in the form of a partial circuit, which exposesportion 422 a of catalyst 422. In step 440, conductor 424 iselectrolytically plated to exposed portion 422 a of catalyst 422, withtemporary resist layer 430 preventing electrolytically plating to anyportion of catalyst 422 covered by layer 430. In step 450, temporaryresist layer 430 is stripped (e.g., chemically stripped) from catalyst422, exposing catalyst 422 and leaving conductor 424 plated to portion422 a and substrate 420, and forming partial circuit 460A. In optionalstep 470, catalyst 422 is further removed (e.g., etched, etc.) fromsubstrate 420, yielding partial circuit 460A.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, partialcircuit 460A will appear as partial circuit 460B including optionallayer 230A as depicted in FIG. 4B, or partial circuit 460C includingoptional layer 230A and further optional layer 240 as depicted in FIG.4C. In the embodiment of FIG. 4D, catalyzed metal foil 200B is used inplace of catalyzed metal foil 310, including organic material layer230B.

FIG. 5 depicts method 500 for manufacturing partial circuit 580 usingcatalyzed substrate 310 of FIG. 3. In step 510, temporary resist layer530 is formed across catalyst 522, deposited on substrate 520 (e.g.,dielectric substrate). Temporary resist layer 530 is formed leavingportions of catalyst 522 a exposed, as depicted. In step 540, exposedportions of catalyst 522 a are removed (e.g., etched, etc.), leavingonly covered portions of catalyst 522 b covered by temporary resistlayer 530. In step 550, temporary resist layer 530 is stripped, exposingthe remaining portion 522 b of catalyst. In step 560, conductor 570 iselectrolytically plated to catalyst 522 b, producing partial circuit580.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, partialcircuit 580 will appear as partial circuit 460B including optional layer230A as depicted in FIG. 4B, or partial circuit 460C including optionallayer 230A and further optional layer 240 as depicted in FIG. 4C. Insome embodiments, catalyzed metal foil 200B can be used in place ofcatalyzed metal foil 310. Partial circuit 580 will appear as partialcircuit 460D including organic material 230B as depicted in FIG. 4D.

FIG. 6 depicts method 600 for manufacturing partial circuit 680 usingcatalyzed substrate 310 of FIG. 3. In step 610, conductor 624 iselectroless plated to catalyst 622, which is deposited on substrate 620.Conductor 624 is plated typically less than 500 μm, 400 μm, 300 μm, 200m, 100 m, or 50 μm thick, or at least a minimum thickness to propagateelectrolytic plating of a conductor. In step 630, temporary resist layer640 is formed over conductor 624, with negative pattern 642 leavingportion 624 a of conductor 624 exposed in the negative pattern of partof a circuit. In step 650, conductor 626 is electrolytically plated toportion 624 a of conductor 624. In step 660, temporary resist layer 640is stripped away, exposing conductor 624. In step 670, exposed portionsof conductor 624 and underlying portions of catalyst 622 are removed(e.g., etched, etc.), producing partial circuit 680.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, partialcircuit 680 will appear as partial circuit 460B including optional layer230A as depicted in FIG. 4B, or partial circuit 460C including optionallayer 230A and further optional layer 240 as depicted in FIG. 4C. Insome embodiments, catalyzed metal foil 200B can be used in place ofcatalyzed metal foil 310. Partial circuit 680 will appear as partialcircuit 460D including organic material 230B as depicted in FIG. 4D.

FIG. 7A depicts method 700 for manufacturing partial embedded circuit750A using catalyzed substrate 310 of FIG. 3. In step 710, permanentresist layer 730 is formed over catalyst 722, which is deposited onsubstrate 720. Permanent resist layer 730 is formed such that negativepattern 732 exposes portion 722 a of catalyst 722. In step 740,conductor 724 is electrolytically plated to the exposed portion 722 a ofcatalyst 722, producing partial embedded circuit 750A.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, partialcircuit 750A will appear as partial circuit 750B including optionallayer 230A as depicted in FIG. 7B, or partial circuit 750C includingoptional layer 230A and further optional layer 240 as depicted in FIG.7C. In the embodiment of FIG. 7D, catalyzed metal foil 200B is used inplace of catalyzed metal foil 310, including organic material layer230B.

FIG. 8 depicts method 800 for manufacturing partial circuit 880 usingcatalyzed substrate 310 of FIG. 3. In step 810, conductor 824 iselectroless plated to catalyst 822, which is deposited on substrate 820.Conductor 824 is plated typically less than 500 m, 400 m, 300 m, 200 m,100 m, or 50 μm thick, or at least a minimum thickness to propagateelectrolytic plating of a conductor. In step 810, conductor 826 iselectrolytically plated to conductor 824, typically to a thickness of atleast 2×, 3×, 4×, 5×, 6×, 7×, 8×, 9×, 10×, or 20x or more the thicknessof conductor 824. In step 840, temporary resist layer 840 is formed onconductor 826 in the pattern of a circuit, leaving exposed portions 826a of conductor 826. In step 860, exposed portions 826 a of conductor826, and portions of catalyst 822 under portions 826 a, are removed(e.g., etched, etc.), leaving portions 826 b of conductor 826 covered bytemporary resist layer 850, and underlying portions 822 b of catalyst822. In step 870, temporary resist layer 850 is stripped, exposingportion 826 b of conductor 826 in the pattern of a circuit, producingpartial circuit 880.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, partialcircuit 880 will appear as partial circuit 460B including optional layer230A as depicted in FIG. 4B, or partial circuit 460C including optionallayer 230A and further optional layer 240 as depicted in FIG. 4C. Insome embodiments, catalyzed metal foil 200B can be used in place ofcatalyzed metal foil 310. Partial circuit 880 will appear as partialcircuit 460D including organic material 230B as depicted in FIG. 4D.

FIG. 9A depicts method 900 for manufacturing catalyzed substrate 970Ausing catalyzed metal foil 910. In step 920, surface 913 (havingcatalyst 914 deposited on it) of catalyzed metal foil 910 is coated withB-stage resin 916. In step 930, the B-stage resin 916, along withcatalyst 914 and metal foil 912, is laminated to surface 944 ofsubstrate 942 (e.g., prepreg, curable film, thermoplastic substrate),producing interim material 950. During the lamination step, B-stageresin 916 is cured to form C-stage resin 917. In step 960, removablemetal foil 912 is etched from interim material 950, forming catalyzedsubstrate 970 having catalyst 914 deposited on cured C-stage resin 917,which is deposited on substrate 942.

While FIG. 9A depicts use of B and C-Stage resins, it is contemplatedthat other materials or resins can be used. For example, polymers,combinations of polymers, or specifically formulated polymers are usedto have beneficial effect, or no effect, on the function or performanceof substrate 942. In cases where substrate 942 includes electricalcircuitry, polymers that bind or adhere well to the substrate are used,preferably polymers that do not alter performance of the circuitry atall or beyond a desired tolerance. Layer 916 or 917 is preferably thin,less than 100 μm, 50 μm, 20 μm, 10 μm, 5 μm, or less than 0.5 μm. Inpreferred embodiments a layer of such polymers or resins between 0.5 μmand 0.1 μm thick, but where practical or favorable can be less than 100nm, less than 50 nm, or less than 10 nm.

In some embodiments, catalyzed metal foil 200A can be used in place ofcatalyzed metal foil 310, for example including optional layer 230A orfurther optional layer 240 as described. In such embodiments, catalyzedsubstrate 970A will appear as catalyzed substrate 970B includingoptional layer 230A as depicted in FIG. 9B, or catalyzed substrate 970Cincluding optional layer 230A and further optional layer 240 as depictedin FIG. 9C. In the embodiment of FIG. 9D, catalyzed metal foil 200B isused in catalyzed substrate 970D in place of catalyzed metal foil 310,including organic material layer 230B.

FIG. 10 depicts a flow chart of process 1000, which includes startingmaterial 1010, interim material 1020, interim material 1030, andfinished material 1040. Starting material 1010 includes removeablematerial 1012 (e.g., etchable metal, etchable aluminum, etchable copper,removeable plastic film, etc.), and catalyst layer 1014 deposited on asurface of removeable metal 1012. Polymer layer 1016 is deposited on asurface of catalyst layer 1014. Preferably, content of polymer layer1016 is specifically selected, designed, or formulated to bind or adherefavorably to the catalyst layer, to a surface of bonding sheet 1022(e.g., prepreg, bonding film, adhesive sheet), or both. For example,polymer layer 1016 can include a single polymer variant with highstrength or binding specificity to bonding sheet 1022, can include anumber of polymer variants with desirable binding or adherence traits,physical tolerance (temperature tolerances, flexibility, durability,etc.), electrical traits (e.g., EM insulation, conductivity,resistivity, dielectric, etc.), or otherwise doped with other materialsto imbue polymer layer 1016 with such desirable properties. Further, inpreferred embodiments polymer layer 1016 is between 1 μm and 0.01 m, butwhere practical or favorable can be less than 500 nm, less than 100 nm,or less than 50 nm. Reducing the separation between catalyst layer 1014and bonding sheet 1022, or moreover between catalyst layer 1014 andsubstrate 1024, is absolutely critical in some embodiments.

Interim material 1020 includes removeable metal 1012, catalyst layer1014, and polymer layer 1016, further including bonding sheet 1022 andsubstrate 1024. As noted, the contents of polymer layer 1016 arepreferably selected to maintain strong binding or adhesion betweencatalyst layer 1014 and a surface of bonding sheet 1022. Likewise,bonding sheet 1022 is selected to maintain strong binding or adhesionbetween bonding sheet 1022 and a surface of substrate 1024. In someembodiments, polymer layer 1016 is selected to maintain strong bindingor adhesion to a broad class of bonding sheets, bonding sheet 1022 isselected to maintain strong binding or adhesion to a broad class ofsubstrates, or both.

Interim material 1030 includes removeable metal 1012, catalyst layer1014, polymer layer 1016, bonding sheet 1022, and substrate 1024 adheredor bonded together as depicted (e.g., laminated). Finished materialresults from removing etchable metal 1012 and exposing a surface ofcatalyst layer 1014. It is contemplated that finished material 1040 canbe further processed to, for example, plate a conductor (electroless,electrolytic, various combinations thereof, etc.) to finished material1040, in a pattern, in bulk, or both. Such methods are useful for addingelectrical transmission lines, circuit patterns, new or improved RFproperties or capabilities, or the like to substrate 1024 or finishedmaterial 1040A, for example when substrate 1024 already includeselectrical circuits or various electronic components with rated,approved, or certified performance tolerances or characteristics.

While FIG. 10 depicts methods and devices for a single sided addition ofa catalyst layer or catalyst coated etchable or removable metal layer toa substrate, it is further contemplated that such teachings are appliedto add catalyst layer or catalyst coated etchable or removable metallayer to more than one part of a substrate, for example multipleportions of a single side of the substrate, portions of more than oneside of the substrate, or multiple portions of multiple sides of thesubstrate.

FIG. 11 depicts a flow chart of process 1100, which includes startingmaterial 1110, interim material 1120, interim material 1130, interimmaterial 1140, and finished material 1150. Starting material 1110includes removeable material 1112 (e.g., etchable metal, etchablealuminum, etchable copper, removeable plastic film, etc.), and catalystlayer 1114 deposited on a surface of removeable metal 1112. Metal oxidelayer 1116 is deposited on a surface of catalyst layer 1114. Preferably,metal oxide layer 1116 is specifically selected, designed, or formulatedto bind or adhere favorably to catalyst layer 1114. Further, metal oxidelayer 1116 preferably protects subsequent polymer layer 118 fromdiffusion and promotes good adhesion of metal oxide layer 1116, andthereby starting materials 1110, to polymer layer 1118.

Interim material 1120 further includes polymer layer 1118, which isdeposited on a surface of metal oxide layer 1116. Preferably, content ofpolymer layer 1118 is specifically selected, designed, or formulated tobind or adhere favorably to catalyst layer 1116, to a surface of bondingsheet 1122 (e.g., prepreg, bonding film, adhesive sheet), to metal oxidelayer 1116, or combinations thereof. For example, polymer layer 1118 caninclude a single polymer variant with high strength or bindingspecificity to bonding sheet 1122, can include a number of polymervariants with desirable binding or adherence traits, physical tolerance(temperature tolerances, flexibility, durability, etc.), or electricaltraits (e.g., EM insulation, conductivity, resistivity, dielectric,etc.), or otherwise doped with other materials to imbue polymer layer1118 with such desirable properties. Further, in preferred embodimentsthe combined thickness of metal oxide layer 1116 and polymer layer 1118is between 1.0 μm and 0.01 m, but where practical or favorable can beless than 500 nm, less than 100 nm, or less than 50 nm. Reducing theseparation between catalyst layer 1114 and bonding sheet 1122, ormoreover between catalyst layer 1114 and substrate 1124, is absolutelycritical in some embodiments.

Interim material 1130 includes removeable metal 1112, catalyst layer1114, metal oxide layer 1116, and polymer layer 1118, further includingbonding sheet 1122 and substrate 1124. As noted, the contents of polymerlayer 1118 are preferably selected to maintain strong binding oradhesion between metal oxide layer 1116 (thereby catalyst layer 1114 andremovable metal 1112) and a surface of bonding sheet 1122. Likewise,bonding sheet 1122 is selected to maintain strong binding or adhesionbetween bonding sheet 1122 and a surface of substrate 1124. In someembodiments, polymer layer 1118 is selected to maintain strong bindingor adhesion to a broad class of bonding sheets, bonding sheet 1122 isselected to maintain strong binding or adhesion to a broad class ofsubstrates, or both.

Interim material 1140 includes removeable metal 1112, catalyst layer1114, metal oxide layer 1116, polymer layer 1118, bonding sheet 1122,and substrate 1124 adhered or bonded together as depicted (e.g.,laminated). Finished material 1150 results from removing removeablemetal 1112 and exposing a surface of catalyst layer 1114. It iscontemplated that finished material 1140 can be further processed to,for example, plate a conductor (electroless, electrolytic, variouscombinations thereof, etc.) to finished material 1150, in a pattern, inbulk, or both. Such methods are useful for adding electricaltransmission lines, circuit patterns, new or improved RF properties orcapabilities, or the like to substrate 1124 or finished material 1150,for example when substrate 1124 already includes electrical circuits orvarious electronic components with rated, approved, or certifiedperformance tolerances or characteristics.

While FIG. 11 depicts methods and devices for a single sided addition ofa catalyst layer or catalyst coated or removable metal layer to asubstrate, it is further contemplated that such teachings are applied toadd catalyst layer or catalyst coated or removable metal layer to morethan one part of a substrate, for example multiple portions of a singleside of the substrate, portions of more than one side of the substrate,or multiple portions of multiple sides of the substrate.

FIG. 12 depicts flow chart 1200 of a method of the inventive subjectmatter, for example to produce an electrical circuit using an etchablemetal foil. Steps 1240, 1250, 1260, and 1270 are considered core stepsthat are shared between alternate sets of precursor steps 1210 and 1212,1220, and 1230, 1232, and 1234. While optional steps 1242 and 1280 arecontemplated, they are not required in all embodiments. Further, whilestep 1242 teaches chemical treatment, it is contemplated the film orsubstrate is treated with a plasma, a corona discharge, or an electronbeam, either alternatively or in combination with chemical treatments.

FIG. 13 depicts flow chart 1300 of a method of the inventive subjectmatter, for example to produce an electrical circuit using a catalyzedmetal foil. Steps 1340, 1350, and 1360 are considered core steps thatare shared between alternate sets of steps 1310 and 1312, 1320 and 1322,and 1330, 1332, and 1334 laminating a catalyzed metal foil over asubstrate with a bonding film. While optional steps 1342 and 1370 arecontemplated, they are not required in all embodiments. Further, whilestep 1342 teaches chemical treatment, it is contemplated the film orsubstrate is treated with a plasma, a corona discharge, or an electronbeam, either alternatively or in combination with chemical treatments.

FIG. 14 depicts process 1400 developing starting materials 1410 infinished or interim material 1430, for example via processes depicted inFIG. 12 or 14. Starting materials 1410 include aluminum foil 1412,bonding film 1414, and laminate 1416. In some embodiments aluminum foilcarries a catalyst precursor or activated catalyst, for example at thesurface facing bonding film 1414. During process steps 1420, aluminumfoil 1412, bonding film 1414, and laminate 1416 are laminated together,and aluminum foil 1412 is etched away leaving behind a precursorcatalyst or activated catalyst on the surface of bonding film 1415.

In embodiments with a catalyst precursor on the surface of bonding film1415, the catalyst precursor is activated, and copper 1440 is otherwiseelectrolessly deposited on the activated catalyst to form finished orinterim material 1430. While bonding film 1414 is substantially the sameas 1415, in some embodiments bonding film 1415 is partially or fullycured compared to bonding film 1414, or otherwise treated with achemical. Likewise, laminate 1416 is substantially the same as 1417,though in some embodiments laminate 1417 is further treated with achemical.

The following discussion provides many example embodiments of theinventive subject matter. Although each embodiment represents a singlecombination of inventive elements, the inventive subject matter isconsidered to include all possible combinations of the disclosedelements. Thus if one embodiment comprises elements A, B, and C, and asecond embodiment comprises elements B and D, then the inventive subjectmatter is also considered to include other remaining combinations of A,B, C, or D, even if not explicitly disclosed.

As used herein, and unless the context dictates otherwise, the term“coupled to” is intended to include both direct coupling (in which twoelements that are coupled to each other contact each other) and indirectcoupling (in which at least one additional element is located betweenthe two elements). Therefore, the terms “coupled to” and “coupled with”are used synonymously.

In some embodiments, the numbers expressing quantities of ingredients,properties such as concentration, reaction conditions, and so forth,used to describe and claim certain embodiments of the invention are tobe understood as being modified in some instances by the term “about.”Accordingly, in some embodiments, the numerical parameters set forth inthe written description and attached claims are approximations that canvary depending upon the desired properties sought to be obtained by aparticular embodiment. In some embodiments, the numerical parametersshould be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeof some embodiments of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspracticable. The numerical values presented in some embodiments of theinvention may contain certain errors necessarily resulting from thestandard deviation found in their respective testing measurements.

Unless the context dictates the contrary, all ranges set forth hereinshould be interpreted as being inclusive of their endpoints, andopen-ended ranges should be interpreted to include only commerciallypractical values. Similarly, all lists of values should be considered asinclusive of intermediate values unless the context indicates thecontrary.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. The use of any and all examples, or exemplary language (e.g.“such as”) provided with respect to certain embodiments herein isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention otherwise claimed. No languagein the specification should be construed as indicating any non-claimedelement essential to the practice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the spirit of theappended claims. Moreover, in interpreting both the specification andthe claims, all terms should be interpreted in the broadest possiblemanner consistent with the context. In particular, the terms “comprises”and “comprising” should be interpreted as referring to elements,components, or steps in a non-exclusive manner, indicating that thereferenced elements, components, or steps may be present, or utilized,or combined with other elements, components, or steps that are notexpressly referenced. Where the specification claims refers to at leastone of something selected from the group consisting of A, B, C . . . andN, the text should be interpreted as requiring only one element from thegroup, not A plus N, or B plus N, etc.

What is claimed is:
 1. A method of forming an electrical circuitcomprising a substrate using a metal foil, the method comprising:laminating a film to a surface of the substrate; laminating a surface ofthe metal foil to the film; removing the metal foil to expose a portionof the film or substrate; and depositing a first conductor to theportion of the film or substrate.
 2. The method of claim 1, wherein thefilm is partially or fully cured.
 3. The method of claim 1, wherein thefilm is partially or fully cured before the step of removing the metalfoil.
 4. The method of claim 1, further comprising the step of treatingthe film or substrate with a chemical.
 5. The method of claim 4, whereinthe chemical is selected from the group consisting of an oxidizer, asolution of permanganate salt, a solution of alkali metal hydroxide, asolution of alkali earth metal hydroxide.
 6. The method of claim 4,wherein the step of laminating the surface of the metal foil to the filmoccurs after the step of treating the film or substrate with thechemical.
 7. The method of claim 1, further comprising the step oftreating the film or substrate with a chemical after the step ofremoving the metal foil.
 8. The method of claim 1, further comprisingthe step of treating the film or substrate with a plasma, a coronadischarge, or an electron beam.
 9. The method of claim 1, wherein thefilm is a bonding film.
 10. The method of claim 9, wherein the bondingfilm is selected from the group comprising a B-stage resin sheet, areinforced B-stage resin sheet, or a prepreg.
 11. The method of claim 1,further comprising the step of applying a catalyst precursor to the filmor substrate and activating the catalyst precursor to a catalyst beforethe step of depositing the first conductor to the portion of the film orsubstrate.
 12. The method of claim 1, wherein the surface of the metalfoil bears a catalyst or a catalyst precursor.
 13. The method of claim 1or 8, wherein the surface of the metal foil bears a catalyst or acatalyst precursor before the step of laminating the surface of themetal foil to the film.
 14. The method of claim 12, wherein the catalystor catalyst precursor remains on the film or substrate after the step ofremoving the metal foil.
 15. The method of claim 12, further comprisingthe step of activating the catalyst precursor before depositing thefirst conductor.
 16. The method of claim 11 or 12, wherein the step ofdepositing the first conductor comprises electroless deposition of thefirst conductor to the catalyst.
 17. The method of claim 1, furthercomprising the step of electrolytically depositing a second conductor onthe first conductor.
 18. The method of claim 1, wherein the metal foilincludes at least one of aluminum, anodized aluminum, copper, tin, oralloys thereof.
 19. The method of claim 1, wherein the step of removingthe metal foil comprises etching the metal foil.